/*******************************************************************************
 * Copyright (c) 2000, 2010 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.internal.ide;

import java.net.URI;

import org.eclipse.core.filesystem.IFileInfo;
import org.eclipse.core.resources.IResource;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.viewers.IDecoration;
import org.eclipse.jface.viewers.ILabelProviderListener;
import org.eclipse.jface.viewers.ILightweightLabelDecorator;
import org.eclipse.ui.internal.ide.dialogs.IDEResourceInfoUtils;
import org.eclipse.ui.plugin.AbstractUIPlugin;

/**
 * A LinkedResourceDecorator decorates an element's image with a linked 
 * resource overlay. 
 * 
 * @since 2.1
 */
public class LinkedResourceDecorator implements ILightweightLabelDecorator {
    private static final ImageDescriptor LINK;

    private static final ImageDescriptor LINK_WARNING;

    static {
        LINK = AbstractUIPlugin.imageDescriptorFromPlugin(
                IDEWorkbenchPlugin.IDE_WORKBENCH,
                "$nl$/icons/full/ovr16/link_ovr.gif"); //$NON-NLS-1$
        LINK_WARNING = AbstractUIPlugin.imageDescriptorFromPlugin(
                IDEWorkbenchPlugin.IDE_WORKBENCH,
                "$nl$/icons/full/ovr16/linkwarn_ovr.gif"); //$NON-NLS-1$
    }

    /**
     * Creates a new <code>LinkedResourceDecorator</code>.
     */
    public LinkedResourceDecorator() {
    }

    /**
     * @see org.eclipse.jface.viewers.IBaseLabelProvider#addListener(ILabelProviderListener)
     */
    public void addListener(ILabelProviderListener listener) {
    }

    /**
     * @see org.eclipse.jface.viewers.IBaseLabelProvider#dispose()
     */
    public void dispose() {
        // no resources to dispose
    }

    /**
     * @see org.eclipse.jface.viewers.IBaseLabelProvider#isLabelProperty(java.lang.Object, java.lang.String)
     */
    public boolean isLabelProperty(Object element, String property) {
        return false;
    }

    /**
     * @see org.eclipse.jface.viewers.IBaseLabelProvider#removeListener(ILabelProviderListener)
     */
    public void removeListener(ILabelProviderListener listener) {
    }

    /**
     * Adds the linked resource overlay if the given element is a linked
     * resource.
     * 
     * @param element element to decorate
     * @param decoration  The decoration we are adding to
     * @see org.eclipse.jface.viewers.ILightweightLabelDecorator#decorate(Object, IDecoration)
     */
    public void decorate(Object element, IDecoration decoration) {

        if (element instanceof IResource == false) {
			return;
		}
        IResource resource = (IResource) element;
        if (resource.isLinked() && !resource.isVirtual()) {
			IFileInfo fileInfo = null;
			URI location = resource.getLocationURI();
			if (location != null) {
				fileInfo = IDEResourceInfoUtils.getFileInfo(location);
			}
			if (fileInfo != null && fileInfo.exists()) {
				decoration.addOverlay(LINK);
			} else {
				decoration.addOverlay(LINK_WARNING);
			}
		}

    }

}
